Bladed spokes and tensiometer?

Discussion in 'Cycling Equipment' started by Alan, Feb 12, 2003.

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  1. Alan

    Alan Guest

    How would you verify the tension of a wheel built with bladed spokes such as Sapim CX-Rays? Would
    the tensiometer readings still be valid?

    alan
     
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  2. Alan-<< How would you verify the tension of a wheel built with bladed spokes such as Sapim CX-Rays?
    Would the tensiometer readings still be valid?

    It is for the new DT tensionometer...

    Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
    (303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"
     
  3. Alan

    Alan Guest

    > It is for the new DT tensionometer...
    >
    No, for the standard Wheelsmith one. Just not sure if the deflection measurement is accurate and
    reliable if I were to use it.

    alan
     
  4. Nick Payne

    Nick Payne Guest

    On mine there is no conversion table for that size of spoke. Even when the spokes are bar tight the
    deflection readings are still very small (10-15). I just used the table column for 0.9x3.1 spokes
    and a fudge factor to account for the spokes only being 0.9x2.3 cross section.

    Nick

    "Alan" <[email protected]> wrote in message news:[email protected]...
    > >
    > > It is for the new DT tensionometer...
    > >
    > No, for the standard Wheelsmith one. Just not sure if the deflection measurement is accurate and
    > reliable if I were to use it.
    >
    > alan
     
  5. Jobst Brandt

    Jobst Brandt Guest

    Nick Payne writes:

    >>>> How would you verify the tension of a wheel built with bladed spokes such as Sapim CX-Rays?
    >>>> Would the tensiometer readings still be valid?

    >>> It is for the new DT tensionometer...

    >> No, for the standard Wheelsmith one. Just not sure if the deflection measurement is accurate and
    >> reliable if I were to use
    >> it.

    > On mine there is no conversion table for that size of spoke. Even when the spokes are bar tight
    > the deflection readings are still very small (10-15). I just used the table column for 0.9x3.1
    > spokes and a fudge factor to account for the spokes only being 0.9x2.3 cross section.

    These instruments all measure across the spoke thickness so the thickness enters into the reading.
    For this reason I built my own instrument that was in small production for a year or so, first under
    Avocet, and then under DT. In all about 120 reached the market. Unfortunately, all such instruments
    are designed by people unclear on the problem.

    The bending stiffness of the spoke also enters into the measurement that is based on the theory that
    the spoke is a flexible strand although it is not entirely so. For that reason a small test load
    that causes little bending must be used, but this in turn requires a precise measuring instrument.
    For that purpose I used a 0.0001 resolution dial gauge.

    In addition, small irregularities in spokes are large enough to distort readings and for this
    purpose my instrument had a "tare" zero adjustment that was set in situ. Currently the tensiometer
    problem is not served as well as it could be.

    Jobst Brandt [email protected] Palo Alto CA
     
  6. Alan

    Alan Guest

    > adjustment that was set in situ. Currently the tensiometer problem is not served as well as it
    > could be.
    >
    So what to do for bladed spokes?? Best guess?

    alan
     
  7. Jobst Brandt

    Jobst Brandt Guest

    Alan who? writes:

    >> adjustment that was set in situ. Currently the tensiometer problem is not served as well as it
    >> could be.

    > So what to do for bladed spokes?? Best guess?

    I use my tensiometer that is accurate for spokes of any thickness less than 2.5mm diameter, a number
    I think approaches the stiff bar of steel size.

    Jobst Brandt [email protected] Palo Alto CA
     
  8. Alan

    Alan Guest

    > I use my tensiometer that is accurate for spokes of any thickness less than 2.5mm diameter, a
    > number I think approaches the stiff bar of steel size.
    >
    I may be confused but aren't all spokes pretty much less than 2.5mm, all of DT's spokes are.

    Alan "confused" Wu
     
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